Re: Problem with iteration

Erik Naggum wrote:

* Raffael Cavallaro
| (defun my-reverse (a-list)
|      (do ((n (- 1) (incf n)) (result '() (cons (nth n a-list) result)))
|          ((= n (- (length a-list) 1))  result )))
 
  yikes.
 
(defun my-reverse (list)
  (do ((reversed (list (pop list))
                 (cons (pop list) reversed)))
      ((endp list) reversed)))

Buggy:

* (my-reverse '())

(NIL)


Gauche Scheme:

(define (my-reverse alist)
  (fold cons '() alist))

(define (my-reverse lst :optional (accum '()))
  (if (null? lst)
    accum
    (my-reverse (cdr lst) (cons (car lst) accum))))